20666505600 has 864 divisors, whose sum is σ = 84803322240. Its totient is φ = 4762828800.

The previous prime is 20666505593. The next prime is 20666505611. The reversal of 20666505600 is 650566602.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 107 ways as a sum of consecutive naturals, for example, 108201505 + ... + 108201695.

Almost surely, 2^20666505600 is an apocalyptic number.

20666505600 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20666505600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42401661120).

20666505600 is an abundant number, since it is smaller than the sum of its proper divisors (64136816640).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20666505600 is a wasteful number, since it uses less digits than its factorization.

20666505600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 268 (or 231 counting only the distinct ones).

The product of its (nonzero) digits is 64800, while the sum is 36.

The spelling of 20666505600 in words is "twenty billion, six hundred sixty-six million, five hundred five thousand, six hundred".